兴安落叶松过伐林枯立木分布格局特征分析

以内蒙古根河林业局潮查林场境内的在20世纪80年代初主伐利用后形成的兴安落叶松过伐林为研究对象,利用兴安落叶松林8块标准地每木定位数据,分析林木分布格局和样方(5 m×5 m)林木株数对枯立木株数影响,探讨了林分大树和更新幼树位置与枯立木位置的关系,阐明了枯立木分布格局形成机制。结果表明:1)各树种枯立木比例,随树种组成成数增加而增大。枯立木主要在更新幼树阶段形成,径级分布集中在4径阶以下,其株数占总数的比例平均达82.2%。在更新幼树(含枯立木)中,生成枯立木的比例平均达8.8%。2)枯立木分布格局为聚集分布。林木分布格局、样方林木株数和更新株数与枯立木株数有显著正相关关系,林木分布格局对枯立木分布格局无显著影响。林木聚集度越大,形成枯立木的可能性越大,数量也就越多。3)枯立木位置与更新幼树和大树位置有显著相关关系。主要表现为落叶松和白桦相互关系。枯立木出现位置主要在大树和更新幼树集聚区域。大树对枯立木形成影响较更新幼树大,而且均以落叶松较白桦明显。白桦更新幼树对落叶松枯立木的形成,无显著影响。受影响的枯立木主要是枯立木株数中所占比例和树种组成成数较高的树种。影响枯立木位置的林木主要取决于其样方内位置和林木株数。

Analysis on Distribution Pattern Characteristics of Standing Dead Trees in Larix gmelinii Overcutting Forest

The Larix gmelinii overcutting forest formed by final cutting in the 1980s at Chaocha Forest Farm, Genhe Forestry Bureau of Inner Mongolia was investigated. Based on the tree's location data of 8 sample plots in the L. gmelinii forest, the impacts of forest stand pattern and quadrat (5 m×5 m) stem-number on the amount of dead standing trees were analyzed, the relationship between the location of big trees and the regeneration saplings and the location of dead standing trees was discussed, and the forming mechanism of distribution pattern of dead standing trees was clarified. The results are as follows. 1. The ratio of dead standing trees increased with the increase of tree species. The dead standing trees were formed mainly in the stage of regeneration saplings, with the diameter class distribution mainly being below the fourth diameter class, and the average ratio of trees accounting for 82.2% of the total. In the regeneration saplings (including dead standing trees), an average ratio of production of dead standing trees is 8.8%. 2. The distribution of dead standing trees followed a aggregated pattern. The forest stand pattern, the quadrat stem-number and the amount of regeneration trees were in a significant correlation with the amount of dead standing trees. The forest stand pattern had not a significant effect on the pattern of dead standing trees. If the degree of aggregation of the forest is greater, the probability of the formation of dead standing trees will be greater, and the amount will be greater. 3. The location of dead standing trees had a significant correlation with the location of regeneration saplings and regeneration big trees. The main performance was the mutual relation between larch and white birch. The location of dead standing trees was mainly at the aggregation area of the big trees and regeneration saplings. Compared to the regeneration saplings, the big trees had greater impact on the dead standing trees, and specifically, the impact from larch was greater than that from the white birch. The white birch's regeneration saplings had not a significant impact on the formation of larch's dead standing trees. The dead standing trees affected were mainly the species with a higher ratio or greater amount of dead standing trees upon the species of trees. The forest that had an impact on dead standing trees depended mainly on the position of the sample trees and the stem-number.